Automatic tuning control for radio systems and the like



Feb. 17, 1948. c K 2,436,172

AUTOMATIC TUNING CONTROL FOR RADIO SYSTEMS AND THE LIKE Filed Dec. 27, 1946 3 Sheets-Sheet 1 INVENTOR RAYMOND C. KENT ATTORN EY R. c. KENT 2,436,172

TUNING CONTROL FOR RADIO SYSTEMS AND THE LIKE 3 Sheets-Sheet 2 Feb. 17, 1948.

AUTOMATIC Filed Dec. 27, 1946 INVENTOR RAYMOND C. KENT ATTORNEY Feb. 17, 1948. R. c. KENT 2,436,172

AUTOMATIC TUNING CONTROL FOR RADIO SYSTEMS AND THE LIKE Filed Dec. 27, 1946 3 Sheets-Sheet 3 g lllllklh- FIG.

INVENTOR RAYMOND C. KENT Wz y ATTORNEY Patented Feb. 17, 1948 AUTOMATIC TUNING CONTROL FOR RADIO SYSTEMS THE LIKE Raymond C. Kent, Cedar Rapids, Iowa, assignor to Collins Radio Company, Cedar Rapids, Iowa,

a corporation of Iowa Application December 27, 1848, Serial No. 718,811 a Claims. (Cl. sis-:1)

This invention relates to automatic controls and more especially to the automatic positioning of control shaft-s for radio apparatus and the like.

A principal object of the invention is to provide a simplified and eflicient electromechanical device for moving a control shaft to any one of a very large number of selected positions.

Another principal object is to provide a selective shaft-positioning unit particularly suited to the tuning or adjusting of radio apparatus. employing a plurality of selective control stages which are arranged to act cumulatively on the -a bank of epicyclic or differential gear units which cooperate to provide a highly flexible system for controlling the selective rotation of a master shaft to any one of a large number of positions, for example as many'as one thousand.

A further feature relates to the novel organization; arrangement and relative interconnection of parts which cooperate to provide an improved automatic radio tuning control device.

Other features and advantages not specifically enumerated will become apparent after a consideration of the following detailed descriptions and the appended claims.

, In :the drawing which shows one preferred embodiment,

Fig. 1 is a front view, partly sectional, of the multi-stage control system according to the invention.

Fig. 2 is a perspective view of one of the switch and gear train units oi. Fig. 1.

Fig. 3 is a partial sectional view of Fig. 1. taken 4 along the line 8-3 thereof.

- Fig. 4 is a detailed schematic wiring diagram of the electrical controls of one oi the stages of Pig. 1.

Referring to Fig. 1, the master shaft M to be selectively controlled or angularly positioned is supported for rotation in suitable bearings in a bracket II, which is fastened to a common base plate l2. Merely for illustration, shaft II is shown connected to the rotary plates ll of an electrostatic tuning condenser l4. It will be understood that any other similar tuning device or circuit element of radio apparatus or the like, can be substituted for the condenser i4 and this device can be connected either directly to shaft lb or through suitable gearing. The system as shown in Fig. 1, is capable of accurately setting the shaft iii in any one of a thousand different rotational settings throughout its 360 of rotation. If desired, shaft 10 may be attached to a, lead screw which cooperates with a lead screw follower in the well-known manner to move a tuning device, such as the magnetic core of a permeability tuning unit to any one of a thousand different longitudinal settings. In general, the system consists of three stages designated respectively A," .B' and 0"; each stage comprising an epicyclic or differential gear unit and an associated automatic rotary selector switch together with a remotely located control box. The gear and switch unit of one of the stages, for example stage "A," is shown in perspective in Fig. 2. The three stages are so interconnected that by the automatic selective control of the stages, either individually or in combination, the shaft it can be rotated to the desired position. Furthermore, the arrangement is such that the stages are cumulative in their control of shaft I0. Thus, if stage A alone is selectively operated, shaft ID will be rotated through successive equal incremental angles of "11 degrees. If stage B is selectively operated, shaft Hi can be turned through successive incremental angles of 1611" degrees; and if stage "0 is operated the shaft I! can be rotated through successive incremental angles of l00n" degrees. In other words, stage C can be considered the hundreds" stage; stage "3 as the tens stage; and stage A as the units stage.

Since all the stages are substantially identical in construction, a detailed description of one stage will suffice. However. the corresponding parts in the three stages shown bear the same designation numerals but with the postscripts a, "b or "c to identify the respective stages. Referring to stage A, it comprises a shaft l5a which is journalled in a suitable bearing bracket "a, so as to freely rotate but to be restrained against longitudinal movement. Fastened to the right-hand end of shaft I So is a gear wheel Ha, which forms the sun gear of an epicyclic or differential train, including a two planetary gear i811, "a, and the ring gear 20a. Planetary gears "a. Na. are respectively rotatablv mounted on stub shafts Ila, 22a, which are fastened to a yoke 4 ring gear 20a has its outer periphery provided with a series of ten ratchet teeth with which the stepping pawl 25:; is adapted to engage so as to rotate the said ring gear in a step-by-step manner under control of the associated stepping magnet 26a. A locking or holding pawl 21a is plvotally supported at a fixed point 28a, to hold the ring gear 20a in its selectively set position. Also associated with each ring gear is a homing control magnet 29a whose armature operates arm 30a, pivoted at 3la, and carrying pins 32a, 33a, which respectively .engage pawls 21a and 25a. Then, when magnet 29a is energized, both pawls 25a and 21a are moved clear of ring gear 291:, which is thereupon free to rotate back to its home or normal position under control of a coiled spiral spring 34a, having one end fastened to a sleeve li on shaft la, and the other end anchored to the base I 2. The ring gear 20a carries a pin 35a, which engages the rigid stop 36a on base l2 when the ring gear reaches its home position.

Attached to the ring gear e. g., by studs Sla,

38a, is a yoke 39a, which is fastened by screw 49a to a sleeve Ma, rotatable around shaft l5a. Also fastened to sleeve Ma is the rotating element or wiper brush 42a of an automatic selector switch of the line finder type. As shown more clearly in Fig. 2, this wiper is in the form of a metal brush. Cooperating with wiper brush 42a is a contact bank comprising a series often contact points Ma, which are circularly arranged and suitably anchored in disc 65a of insulating material, this disc being fixedly supported for example by angle members to bracket lilo. Likewise, brush dZa is connected to a slip ring Add on sleeve Ma with which a fixed brush dla contacts. An additional homing contact 52a is provided between the and #1 contacts as schematically shown in Fig. 4. Suitable wiring lugs 48a are provided for connecting the respective bank contacts into circuit. Brush 42a is arranged to be remotely controlled from the associated control box which includes a manually rotatable switch silo, whose metal wiper disc 50a can be turned until its cut-out notch 63a registers with the desired one of ten fixed contacts 5m.

The control box 56a for unit A, can be located at any suitable remote point and in addition to the manual selector switch 49a it includes a homing control relay a and an interlock relaybfia.

The fixed contacts 51a of switch 49a are multipled to the corresponding fixed bank contacts 64a. The arrangement is such that by turning the disc 50a to the desired contact, the magnet 26a is given an impulse to turn the brush 42a step-by-step to each succeeding contact Ma. When the selected contact Add is found by brush 62c, the circuit of the stepping magnet 25a is finally broken, thus stopping the ring gear 26a, and the shaft it. By well-known principles of eplcycllc gearing, and by suitable design of the number of teeth and diameter of the gears, each step of ring gear 20a will cause a corresponding angular rotation of shaft iii. the ring gears are each designed to have steps of 30 per ratchet tooth, the shaft it! may move .27 degree for each step of gear 20a; 2.7 degrees for each step of gear 20b, and 27 degrees for each step of gear 200. These incremental steps may be chosen by using ring gears having appropriate angles on the ratchet teeth. While of course the rotation of shaft I0 is limited to 360 C., if desired,

For example, if'

4 a step-up gear ratio can be provided between shaft l0 and the. device [6.

Referring to Fig. 4, a description will be given or the electrical interlocking and control circuits for the unit "A," it being understood that each of the remaining units has similar sets 01' circuits.

In Fig. 4, the unit "A" had been previously obj-- 'erated so as to selectively move the ring gear 20d only one step as indicated by the position of switch arm 50a on #1 contact. a. new setting is required for shaft id e. g., one requiring four steps of ring gear 29a. For that purpose, disc 50a is manually moved to #4 contact, thus completing a circuit from the positive battery terminal 57a, brush 62a, #1 contact, con ductor 58a, #1 contact of switch 69a, disc efla, winding of stepping magnet 25a to ground through contacts 60a of the relay 55a. This causes brush 42a and ring gear 200 to rotate in a step-by-step manner until the brush 42a comes into registry with the selected #4 contact, whereupon the circuit for magnet 26a is finally broken and the ring 2011 comes to rest. As a result of the rotation 01 ring gear 20a, sun gear llb is rotated, in turn rotating planetary gears Idb, l9b, shaft I50, planetary gears 58c, ltc, and shaft id.

The above description is on the assumption that the brush 6211 was originally set on contact #1 and is selectively moved clockwise to contact #4. If however for example, switch arm 62a is now to be selectively moved to contact #3, disc 50a is moved so that notch 53a registers with contact #3, the stepping switch magnet Zea will then operate as above described and will step the gear 20a and the brush 32a in'search of the open #3 contact. However, as the brush 55M passes by the homing contact 62a, both relays 29a and 55a; are operated in parallel from the battery 57a. Since relay 55c operates, it closes a holding circuit for itself traceable from the positive battery terminal 51a through the normally closed contacts 6m of relay 58a, through the operated contacts 62a of relay 55a and thence through the windings of relay 55a to ground. The operation of relay the opens the circuit of the stepping magnet 26. Since magnet 29c operates, it moves both of the parts 25a and 27a out of the path of the ring gear 26a which immediately restores to normal under control of its spring 8 3a carrying with it the brush 32a. As the brushdsa reaches #1 contact, it closes an operating circuit for interlock relay 58a traceable from ground through the winding of relay 56a, #1 contact, brush 62a to positive battery terminal 57a. Relay 5% in operating opens the holding circuit for relay the stepping magnet 2641 again to be energized in step-by-step manner so as to advance the brush 62a in search of the #3 contact, whereupon the circuit of the stepping magnet 26:: is finally opened as above described, thus completing the cycle of operations.

What is claimed is:

1. An automatic shaft positioning system for radio control apparatus and the like, comprising a plurality of-shait positioning stages each ineluding an epicyclic gear train and an associated automatic selector switch of the line finder type, the sun gear of one epicyclic stage being driven from the planetary gear of the preceding stage, and the automatic switch of each stage being connected to revolve as a unit with the planetary gear thereof.

2. An automatic shaft positioning system for It will be assumed that 55a. This allows including an automatic switch of the line finder type, an epicyclic gear train for each train, a step-by-step operating magnet for advancing the ring gear of each stage a selected number of steps under control of the associated finder switch, and means connecting the planetary gear of each stage to the sun gear of a succeeding stage, the sun gear of the final stage being connected to the shaft to be controlled.

3. An automatic shaft positioning system for radio control apparatus and the like, comprising a plurality of shaft positioning stages each including an automatic switch and an epicyclic train, the ring gear of each train having a ratchet toothed periphery, a stepping magnet for each ring gear and having a member for cooperating with the ratchet teeth thereof, means connecting the ring gear of each stage with the rotatable wiper of the associated automatic switch for rotation as a unit therewith, an operating circuit for each stepping magnet, and circuit means effective when each switch reaches a predetermined selected position for opening the circuit of the associated stepping magnet.

4. An automatic shaft positioning system for radio control apparatus and the like, comprising an epicyclic gear train having its sun gear connected to the shaft to be positioned, an automatic selector switch of the line finder type having a wiper rotatable as-a unit with the ring gear of said gear train, and means to operate said ring gear selectively step-by-step, the last-mentioned means including a stepping magnet for said ring gear which is automatically impulsed until said wiper reaches a selected position.

5. An automatic shaft positioning system for radio control apparatus and the like, comprising an epicyclic gear'train having its sun gear connected to the shaft to be positioned, an automatic selector switch of the step-by-step hunting type having a rotatable wiper element rotatable as a unit with the ring gear of. said gear train, spring return means tending to return said wiper and ring gear to a homing position, a stepping magnet having a member cooperating with said ring gear to operate it in a step-bystep manner, a circuit for said stepping magnet switch, and another magnet having a member for operating the first-mentioned member to permit said ring gear and switch to return to normal and thereafter permitting said ring gear and switch to automatically advance to a selected position under control of said stepping magnet.

6. An automatic shaft positioning system according to claim 5 in which the sun gear of said epicyclic gear train is driven from the planetary gear of another epicyclic gear train, and means are provided for selectively operating the ring gear of said other gear train in a step-by-step manner and including a second automatic selector switch of the hunting type and a stepping magnet for said second selector switch.

7. An automatic tuning control device for radio sets and the like, comprising a master shaft to be selectively positioned, a units shaft control stage, a tens shaft control stage, a hundreds" shaft control stage, each stage having an individual and selectively operable gear train, means connecting said gear trains to said shaft to position said shaft under control of an one of said stages individually or cumulatively under control of a plurality of said stages, and means including an automatic selector switch of the finder type for each stage for controlling the selective operation of the gear train thereof.

8; An automatic tuning control device according to claim '7 in which each stage includes an epicyclic gear train whose ring gear is provided with spring means tending normally to return it together with its associated selector switch to a homo position.

RAYMOND C. KENT.

REFERENCES CITED UNITED STATES PATENTS Name Date Kaminski Sept. 16, 1924 Number 

